Onnara is a form of underwear for women of all ages. It is the traditional underwear among the Hindu women in Kerala (southern most state of India). A cotton (handloom) cloth of size 6 muzham X 3 muzham (1 muzam = 1.5 ft approx.) is used to drape around the waist, in a particular style) under the outer garment (pavada, saree, or mundu). Onnara (Thaar) is an undergarment for women, and is not for males.

Onnara is also called "Thaar", in some parts of the State. The word is more often used in the southern part of Kerala; Onnara is mostly a northern Kerala usage. However, there are certain differences in wearing Thaar, over Onnara. Thaar is simpler than the Onnara in the wearing style. There are different types of Thaar too.